samples/simplistic_editor/lib/text_editing_delta_history_manager.dart

import 'package:flutter/services.dart' show TextEditingDelta;
import 'package:flutter/widgets.dart';

/// Signature for the callback that updates text editing delta history when a new delta
/// is received.
typedef TextEditingDeltaHistoryUpdateCallback = void Function(
    List<TextEditingDelta> textEditingDeltas);

class TextEditingDeltaHistoryManager extends InheritedWidget {
  const TextEditingDeltaHistoryManager({
    super.key,
    required super.child,
    required List<TextEditingDelta> history,
    required TextEditingDeltaHistoryUpdateCallback updateHistoryOnInput,
  })  : _textEditingDeltaHistory = history,
        _updateTextEditingDeltaHistoryOnInput = updateHistoryOnInput;

  static TextEditingDeltaHistoryManager of(BuildContext context) {
    final TextEditingDeltaHistoryManager? result = context
        .dependOnInheritedWidgetOfExactType<TextEditingDeltaHistoryManager>();
    assert(
        result != null, 'No TextEditingDeltaHistoryManager found in context');
    return result!;
  }

  final List<TextEditingDelta> _textEditingDeltaHistory;
  final TextEditingDeltaHistoryUpdateCallback
      _updateTextEditingDeltaHistoryOnInput;

  List<TextEditingDelta> get textEditingDeltaHistory =>
      _textEditingDeltaHistory;
  TextEditingDeltaHistoryUpdateCallback
      get updateTextEditingDeltaHistoryOnInput =>
          _updateTextEditingDeltaHistoryOnInput;

  @override
  bool updateShouldNotify(TextEditingDeltaHistoryManager oldWidget) {
    return textEditingDeltaHistory != oldWidget.textEditingDeltaHistory;
  }
}